flow_dissector.c 38 KB

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  1. #include <linux/kernel.h>
  2. #include <linux/skbuff.h>
  3. #include <linux/export.h>
  4. #include <linux/ip.h>
  5. #include <linux/ipv6.h>
  6. #include <linux/if_vlan.h>
  7. #include <net/dsa.h>
  8. #include <net/dst_metadata.h>
  9. #include <net/ip.h>
  10. #include <net/ipv6.h>
  11. #include <net/gre.h>
  12. #include <net/pptp.h>
  13. #include <net/tipc.h>
  14. #include <linux/igmp.h>
  15. #include <linux/icmp.h>
  16. #include <linux/sctp.h>
  17. #include <linux/dccp.h>
  18. #include <linux/if_tunnel.h>
  19. #include <linux/if_pppox.h>
  20. #include <linux/ppp_defs.h>
  21. #include <linux/stddef.h>
  22. #include <linux/if_ether.h>
  23. #include <linux/mpls.h>
  24. #include <linux/tcp.h>
  25. #include <net/flow_dissector.h>
  26. #include <scsi/fc/fc_fcoe.h>
  27. #include <uapi/linux/batadv_packet.h>
  28. static void dissector_set_key(struct flow_dissector *flow_dissector,
  29. enum flow_dissector_key_id key_id)
  30. {
  31. flow_dissector->used_keys |= (1 << key_id);
  32. }
  33. void skb_flow_dissector_init(struct flow_dissector *flow_dissector,
  34. const struct flow_dissector_key *key,
  35. unsigned int key_count)
  36. {
  37. unsigned int i;
  38. memset(flow_dissector, 0, sizeof(*flow_dissector));
  39. for (i = 0; i < key_count; i++, key++) {
  40. /* User should make sure that every key target offset is withing
  41. * boundaries of unsigned short.
  42. */
  43. BUG_ON(key->offset > USHRT_MAX);
  44. BUG_ON(dissector_uses_key(flow_dissector,
  45. key->key_id));
  46. dissector_set_key(flow_dissector, key->key_id);
  47. flow_dissector->offset[key->key_id] = key->offset;
  48. }
  49. /* Ensure that the dissector always includes control and basic key.
  50. * That way we are able to avoid handling lack of these in fast path.
  51. */
  52. BUG_ON(!dissector_uses_key(flow_dissector,
  53. FLOW_DISSECTOR_KEY_CONTROL));
  54. BUG_ON(!dissector_uses_key(flow_dissector,
  55. FLOW_DISSECTOR_KEY_BASIC));
  56. }
  57. EXPORT_SYMBOL(skb_flow_dissector_init);
  58. /**
  59. * skb_flow_get_be16 - extract be16 entity
  60. * @skb: sk_buff to extract from
  61. * @poff: offset to extract at
  62. * @data: raw buffer pointer to the packet
  63. * @hlen: packet header length
  64. *
  65. * The function will try to retrieve a be32 entity at
  66. * offset poff
  67. */
  68. static __be16 skb_flow_get_be16(const struct sk_buff *skb, int poff,
  69. void *data, int hlen)
  70. {
  71. __be16 *u, _u;
  72. u = __skb_header_pointer(skb, poff, sizeof(_u), data, hlen, &_u);
  73. if (u)
  74. return *u;
  75. return 0;
  76. }
  77. /**
  78. * __skb_flow_get_ports - extract the upper layer ports and return them
  79. * @skb: sk_buff to extract the ports from
  80. * @thoff: transport header offset
  81. * @ip_proto: protocol for which to get port offset
  82. * @data: raw buffer pointer to the packet, if NULL use skb->data
  83. * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
  84. *
  85. * The function will try to retrieve the ports at offset thoff + poff where poff
  86. * is the protocol port offset returned from proto_ports_offset
  87. */
  88. __be32 __skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8 ip_proto,
  89. void *data, int hlen)
  90. {
  91. int poff = proto_ports_offset(ip_proto);
  92. if (!data) {
  93. data = skb->data;
  94. hlen = skb_headlen(skb);
  95. }
  96. if (poff >= 0) {
  97. __be32 *ports, _ports;
  98. ports = __skb_header_pointer(skb, thoff + poff,
  99. sizeof(_ports), data, hlen, &_ports);
  100. if (ports)
  101. return *ports;
  102. }
  103. return 0;
  104. }
  105. EXPORT_SYMBOL(__skb_flow_get_ports);
  106. static void
  107. skb_flow_dissect_set_enc_addr_type(enum flow_dissector_key_id type,
  108. struct flow_dissector *flow_dissector,
  109. void *target_container)
  110. {
  111. struct flow_dissector_key_control *ctrl;
  112. if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_CONTROL))
  113. return;
  114. ctrl = skb_flow_dissector_target(flow_dissector,
  115. FLOW_DISSECTOR_KEY_ENC_CONTROL,
  116. target_container);
  117. ctrl->addr_type = type;
  118. }
  119. void
  120. skb_flow_dissect_tunnel_info(const struct sk_buff *skb,
  121. struct flow_dissector *flow_dissector,
  122. void *target_container)
  123. {
  124. struct ip_tunnel_info *info;
  125. struct ip_tunnel_key *key;
  126. /* A quick check to see if there might be something to do. */
  127. if (!dissector_uses_key(flow_dissector,
  128. FLOW_DISSECTOR_KEY_ENC_KEYID) &&
  129. !dissector_uses_key(flow_dissector,
  130. FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS) &&
  131. !dissector_uses_key(flow_dissector,
  132. FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS) &&
  133. !dissector_uses_key(flow_dissector,
  134. FLOW_DISSECTOR_KEY_ENC_CONTROL) &&
  135. !dissector_uses_key(flow_dissector,
  136. FLOW_DISSECTOR_KEY_ENC_PORTS) &&
  137. !dissector_uses_key(flow_dissector,
  138. FLOW_DISSECTOR_KEY_ENC_IP) &&
  139. !dissector_uses_key(flow_dissector,
  140. FLOW_DISSECTOR_KEY_ENC_OPTS))
  141. return;
  142. info = skb_tunnel_info(skb);
  143. if (!info)
  144. return;
  145. key = &info->key;
  146. switch (ip_tunnel_info_af(info)) {
  147. case AF_INET:
  148. skb_flow_dissect_set_enc_addr_type(FLOW_DISSECTOR_KEY_IPV4_ADDRS,
  149. flow_dissector,
  150. target_container);
  151. if (dissector_uses_key(flow_dissector,
  152. FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS)) {
  153. struct flow_dissector_key_ipv4_addrs *ipv4;
  154. ipv4 = skb_flow_dissector_target(flow_dissector,
  155. FLOW_DISSECTOR_KEY_ENC_IPV4_ADDRS,
  156. target_container);
  157. ipv4->src = key->u.ipv4.src;
  158. ipv4->dst = key->u.ipv4.dst;
  159. }
  160. break;
  161. case AF_INET6:
  162. skb_flow_dissect_set_enc_addr_type(FLOW_DISSECTOR_KEY_IPV6_ADDRS,
  163. flow_dissector,
  164. target_container);
  165. if (dissector_uses_key(flow_dissector,
  166. FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS)) {
  167. struct flow_dissector_key_ipv6_addrs *ipv6;
  168. ipv6 = skb_flow_dissector_target(flow_dissector,
  169. FLOW_DISSECTOR_KEY_ENC_IPV6_ADDRS,
  170. target_container);
  171. ipv6->src = key->u.ipv6.src;
  172. ipv6->dst = key->u.ipv6.dst;
  173. }
  174. break;
  175. }
  176. if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_KEYID)) {
  177. struct flow_dissector_key_keyid *keyid;
  178. keyid = skb_flow_dissector_target(flow_dissector,
  179. FLOW_DISSECTOR_KEY_ENC_KEYID,
  180. target_container);
  181. keyid->keyid = tunnel_id_to_key32(key->tun_id);
  182. }
  183. if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_PORTS)) {
  184. struct flow_dissector_key_ports *tp;
  185. tp = skb_flow_dissector_target(flow_dissector,
  186. FLOW_DISSECTOR_KEY_ENC_PORTS,
  187. target_container);
  188. tp->src = key->tp_src;
  189. tp->dst = key->tp_dst;
  190. }
  191. if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_IP)) {
  192. struct flow_dissector_key_ip *ip;
  193. ip = skb_flow_dissector_target(flow_dissector,
  194. FLOW_DISSECTOR_KEY_ENC_IP,
  195. target_container);
  196. ip->tos = key->tos;
  197. ip->ttl = key->ttl;
  198. }
  199. if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ENC_OPTS)) {
  200. struct flow_dissector_key_enc_opts *enc_opt;
  201. enc_opt = skb_flow_dissector_target(flow_dissector,
  202. FLOW_DISSECTOR_KEY_ENC_OPTS,
  203. target_container);
  204. if (info->options_len) {
  205. enc_opt->len = info->options_len;
  206. ip_tunnel_info_opts_get(enc_opt->data, info);
  207. enc_opt->dst_opt_type = info->key.tun_flags &
  208. TUNNEL_OPTIONS_PRESENT;
  209. }
  210. }
  211. }
  212. EXPORT_SYMBOL(skb_flow_dissect_tunnel_info);
  213. static enum flow_dissect_ret
  214. __skb_flow_dissect_mpls(const struct sk_buff *skb,
  215. struct flow_dissector *flow_dissector,
  216. void *target_container, void *data, int nhoff, int hlen)
  217. {
  218. struct flow_dissector_key_keyid *key_keyid;
  219. struct mpls_label *hdr, _hdr[2];
  220. u32 entry, label;
  221. if (!dissector_uses_key(flow_dissector,
  222. FLOW_DISSECTOR_KEY_MPLS_ENTROPY) &&
  223. !dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS))
  224. return FLOW_DISSECT_RET_OUT_GOOD;
  225. hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
  226. hlen, &_hdr);
  227. if (!hdr)
  228. return FLOW_DISSECT_RET_OUT_BAD;
  229. entry = ntohl(hdr[0].entry);
  230. label = (entry & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT;
  231. if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_MPLS)) {
  232. struct flow_dissector_key_mpls *key_mpls;
  233. key_mpls = skb_flow_dissector_target(flow_dissector,
  234. FLOW_DISSECTOR_KEY_MPLS,
  235. target_container);
  236. key_mpls->mpls_label = label;
  237. key_mpls->mpls_ttl = (entry & MPLS_LS_TTL_MASK)
  238. >> MPLS_LS_TTL_SHIFT;
  239. key_mpls->mpls_tc = (entry & MPLS_LS_TC_MASK)
  240. >> MPLS_LS_TC_SHIFT;
  241. key_mpls->mpls_bos = (entry & MPLS_LS_S_MASK)
  242. >> MPLS_LS_S_SHIFT;
  243. }
  244. if (label == MPLS_LABEL_ENTROPY) {
  245. key_keyid = skb_flow_dissector_target(flow_dissector,
  246. FLOW_DISSECTOR_KEY_MPLS_ENTROPY,
  247. target_container);
  248. key_keyid->keyid = hdr[1].entry & htonl(MPLS_LS_LABEL_MASK);
  249. }
  250. return FLOW_DISSECT_RET_OUT_GOOD;
  251. }
  252. static enum flow_dissect_ret
  253. __skb_flow_dissect_arp(const struct sk_buff *skb,
  254. struct flow_dissector *flow_dissector,
  255. void *target_container, void *data, int nhoff, int hlen)
  256. {
  257. struct flow_dissector_key_arp *key_arp;
  258. struct {
  259. unsigned char ar_sha[ETH_ALEN];
  260. unsigned char ar_sip[4];
  261. unsigned char ar_tha[ETH_ALEN];
  262. unsigned char ar_tip[4];
  263. } *arp_eth, _arp_eth;
  264. const struct arphdr *arp;
  265. struct arphdr _arp;
  266. if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_ARP))
  267. return FLOW_DISSECT_RET_OUT_GOOD;
  268. arp = __skb_header_pointer(skb, nhoff, sizeof(_arp), data,
  269. hlen, &_arp);
  270. if (!arp)
  271. return FLOW_DISSECT_RET_OUT_BAD;
  272. if (arp->ar_hrd != htons(ARPHRD_ETHER) ||
  273. arp->ar_pro != htons(ETH_P_IP) ||
  274. arp->ar_hln != ETH_ALEN ||
  275. arp->ar_pln != 4 ||
  276. (arp->ar_op != htons(ARPOP_REPLY) &&
  277. arp->ar_op != htons(ARPOP_REQUEST)))
  278. return FLOW_DISSECT_RET_OUT_BAD;
  279. arp_eth = __skb_header_pointer(skb, nhoff + sizeof(_arp),
  280. sizeof(_arp_eth), data,
  281. hlen, &_arp_eth);
  282. if (!arp_eth)
  283. return FLOW_DISSECT_RET_OUT_BAD;
  284. key_arp = skb_flow_dissector_target(flow_dissector,
  285. FLOW_DISSECTOR_KEY_ARP,
  286. target_container);
  287. memcpy(&key_arp->sip, arp_eth->ar_sip, sizeof(key_arp->sip));
  288. memcpy(&key_arp->tip, arp_eth->ar_tip, sizeof(key_arp->tip));
  289. /* Only store the lower byte of the opcode;
  290. * this covers ARPOP_REPLY and ARPOP_REQUEST.
  291. */
  292. key_arp->op = ntohs(arp->ar_op) & 0xff;
  293. ether_addr_copy(key_arp->sha, arp_eth->ar_sha);
  294. ether_addr_copy(key_arp->tha, arp_eth->ar_tha);
  295. return FLOW_DISSECT_RET_OUT_GOOD;
  296. }
  297. static enum flow_dissect_ret
  298. __skb_flow_dissect_gre(const struct sk_buff *skb,
  299. struct flow_dissector_key_control *key_control,
  300. struct flow_dissector *flow_dissector,
  301. void *target_container, void *data,
  302. __be16 *p_proto, int *p_nhoff, int *p_hlen,
  303. unsigned int flags)
  304. {
  305. struct flow_dissector_key_keyid *key_keyid;
  306. struct gre_base_hdr *hdr, _hdr;
  307. int offset = 0;
  308. u16 gre_ver;
  309. hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr),
  310. data, *p_hlen, &_hdr);
  311. if (!hdr)
  312. return FLOW_DISSECT_RET_OUT_BAD;
  313. /* Only look inside GRE without routing */
  314. if (hdr->flags & GRE_ROUTING)
  315. return FLOW_DISSECT_RET_OUT_GOOD;
  316. /* Only look inside GRE for version 0 and 1 */
  317. gre_ver = ntohs(hdr->flags & GRE_VERSION);
  318. if (gre_ver > 1)
  319. return FLOW_DISSECT_RET_OUT_GOOD;
  320. *p_proto = hdr->protocol;
  321. if (gre_ver) {
  322. /* Version1 must be PPTP, and check the flags */
  323. if (!(*p_proto == GRE_PROTO_PPP && (hdr->flags & GRE_KEY)))
  324. return FLOW_DISSECT_RET_OUT_GOOD;
  325. }
  326. offset += sizeof(struct gre_base_hdr);
  327. if (hdr->flags & GRE_CSUM)
  328. offset += sizeof(((struct gre_full_hdr *) 0)->csum) +
  329. sizeof(((struct gre_full_hdr *) 0)->reserved1);
  330. if (hdr->flags & GRE_KEY) {
  331. const __be32 *keyid;
  332. __be32 _keyid;
  333. keyid = __skb_header_pointer(skb, *p_nhoff + offset,
  334. sizeof(_keyid),
  335. data, *p_hlen, &_keyid);
  336. if (!keyid)
  337. return FLOW_DISSECT_RET_OUT_BAD;
  338. if (dissector_uses_key(flow_dissector,
  339. FLOW_DISSECTOR_KEY_GRE_KEYID)) {
  340. key_keyid = skb_flow_dissector_target(flow_dissector,
  341. FLOW_DISSECTOR_KEY_GRE_KEYID,
  342. target_container);
  343. if (gre_ver == 0)
  344. key_keyid->keyid = *keyid;
  345. else
  346. key_keyid->keyid = *keyid & GRE_PPTP_KEY_MASK;
  347. }
  348. offset += sizeof(((struct gre_full_hdr *) 0)->key);
  349. }
  350. if (hdr->flags & GRE_SEQ)
  351. offset += sizeof(((struct pptp_gre_header *) 0)->seq);
  352. if (gre_ver == 0) {
  353. if (*p_proto == htons(ETH_P_TEB)) {
  354. const struct ethhdr *eth;
  355. struct ethhdr _eth;
  356. eth = __skb_header_pointer(skb, *p_nhoff + offset,
  357. sizeof(_eth),
  358. data, *p_hlen, &_eth);
  359. if (!eth)
  360. return FLOW_DISSECT_RET_OUT_BAD;
  361. *p_proto = eth->h_proto;
  362. offset += sizeof(*eth);
  363. /* Cap headers that we access via pointers at the
  364. * end of the Ethernet header as our maximum alignment
  365. * at that point is only 2 bytes.
  366. */
  367. if (NET_IP_ALIGN)
  368. *p_hlen = *p_nhoff + offset;
  369. }
  370. } else { /* version 1, must be PPTP */
  371. u8 _ppp_hdr[PPP_HDRLEN];
  372. u8 *ppp_hdr;
  373. if (hdr->flags & GRE_ACK)
  374. offset += sizeof(((struct pptp_gre_header *) 0)->ack);
  375. ppp_hdr = __skb_header_pointer(skb, *p_nhoff + offset,
  376. sizeof(_ppp_hdr),
  377. data, *p_hlen, _ppp_hdr);
  378. if (!ppp_hdr)
  379. return FLOW_DISSECT_RET_OUT_BAD;
  380. switch (PPP_PROTOCOL(ppp_hdr)) {
  381. case PPP_IP:
  382. *p_proto = htons(ETH_P_IP);
  383. break;
  384. case PPP_IPV6:
  385. *p_proto = htons(ETH_P_IPV6);
  386. break;
  387. default:
  388. /* Could probably catch some more like MPLS */
  389. break;
  390. }
  391. offset += PPP_HDRLEN;
  392. }
  393. *p_nhoff += offset;
  394. key_control->flags |= FLOW_DIS_ENCAPSULATION;
  395. if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
  396. return FLOW_DISSECT_RET_OUT_GOOD;
  397. return FLOW_DISSECT_RET_PROTO_AGAIN;
  398. }
  399. /**
  400. * __skb_flow_dissect_batadv() - dissect batman-adv header
  401. * @skb: sk_buff to with the batman-adv header
  402. * @key_control: flow dissectors control key
  403. * @data: raw buffer pointer to the packet, if NULL use skb->data
  404. * @p_proto: pointer used to update the protocol to process next
  405. * @p_nhoff: pointer used to update inner network header offset
  406. * @hlen: packet header length
  407. * @flags: any combination of FLOW_DISSECTOR_F_*
  408. *
  409. * ETH_P_BATMAN packets are tried to be dissected. Only
  410. * &struct batadv_unicast packets are actually processed because they contain an
  411. * inner ethernet header and are usually followed by actual network header. This
  412. * allows the flow dissector to continue processing the packet.
  413. *
  414. * Return: FLOW_DISSECT_RET_PROTO_AGAIN when &struct batadv_unicast was found,
  415. * FLOW_DISSECT_RET_OUT_GOOD when dissector should stop after encapsulation,
  416. * otherwise FLOW_DISSECT_RET_OUT_BAD
  417. */
  418. static enum flow_dissect_ret
  419. __skb_flow_dissect_batadv(const struct sk_buff *skb,
  420. struct flow_dissector_key_control *key_control,
  421. void *data, __be16 *p_proto, int *p_nhoff, int hlen,
  422. unsigned int flags)
  423. {
  424. struct {
  425. struct batadv_unicast_packet batadv_unicast;
  426. struct ethhdr eth;
  427. } *hdr, _hdr;
  428. hdr = __skb_header_pointer(skb, *p_nhoff, sizeof(_hdr), data, hlen,
  429. &_hdr);
  430. if (!hdr)
  431. return FLOW_DISSECT_RET_OUT_BAD;
  432. if (hdr->batadv_unicast.version != BATADV_COMPAT_VERSION)
  433. return FLOW_DISSECT_RET_OUT_BAD;
  434. if (hdr->batadv_unicast.packet_type != BATADV_UNICAST)
  435. return FLOW_DISSECT_RET_OUT_BAD;
  436. *p_proto = hdr->eth.h_proto;
  437. *p_nhoff += sizeof(*hdr);
  438. key_control->flags |= FLOW_DIS_ENCAPSULATION;
  439. if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP)
  440. return FLOW_DISSECT_RET_OUT_GOOD;
  441. return FLOW_DISSECT_RET_PROTO_AGAIN;
  442. }
  443. static void
  444. __skb_flow_dissect_tcp(const struct sk_buff *skb,
  445. struct flow_dissector *flow_dissector,
  446. void *target_container, void *data, int thoff, int hlen)
  447. {
  448. struct flow_dissector_key_tcp *key_tcp;
  449. struct tcphdr *th, _th;
  450. if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_TCP))
  451. return;
  452. th = __skb_header_pointer(skb, thoff, sizeof(_th), data, hlen, &_th);
  453. if (!th)
  454. return;
  455. if (unlikely(__tcp_hdrlen(th) < sizeof(_th)))
  456. return;
  457. key_tcp = skb_flow_dissector_target(flow_dissector,
  458. FLOW_DISSECTOR_KEY_TCP,
  459. target_container);
  460. key_tcp->flags = (*(__be16 *) &tcp_flag_word(th) & htons(0x0FFF));
  461. }
  462. static void
  463. __skb_flow_dissect_ipv4(const struct sk_buff *skb,
  464. struct flow_dissector *flow_dissector,
  465. void *target_container, void *data, const struct iphdr *iph)
  466. {
  467. struct flow_dissector_key_ip *key_ip;
  468. if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IP))
  469. return;
  470. key_ip = skb_flow_dissector_target(flow_dissector,
  471. FLOW_DISSECTOR_KEY_IP,
  472. target_container);
  473. key_ip->tos = iph->tos;
  474. key_ip->ttl = iph->ttl;
  475. }
  476. static void
  477. __skb_flow_dissect_ipv6(const struct sk_buff *skb,
  478. struct flow_dissector *flow_dissector,
  479. void *target_container, void *data, const struct ipv6hdr *iph)
  480. {
  481. struct flow_dissector_key_ip *key_ip;
  482. if (!dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_IP))
  483. return;
  484. key_ip = skb_flow_dissector_target(flow_dissector,
  485. FLOW_DISSECTOR_KEY_IP,
  486. target_container);
  487. key_ip->tos = ipv6_get_dsfield(iph);
  488. key_ip->ttl = iph->hop_limit;
  489. }
  490. /* Maximum number of protocol headers that can be parsed in
  491. * __skb_flow_dissect
  492. */
  493. #define MAX_FLOW_DISSECT_HDRS 15
  494. static bool skb_flow_dissect_allowed(int *num_hdrs)
  495. {
  496. ++*num_hdrs;
  497. return (*num_hdrs <= MAX_FLOW_DISSECT_HDRS);
  498. }
  499. /**
  500. * __skb_flow_dissect - extract the flow_keys struct and return it
  501. * @skb: sk_buff to extract the flow from, can be NULL if the rest are specified
  502. * @flow_dissector: list of keys to dissect
  503. * @target_container: target structure to put dissected values into
  504. * @data: raw buffer pointer to the packet, if NULL use skb->data
  505. * @proto: protocol for which to get the flow, if @data is NULL use skb->protocol
  506. * @nhoff: network header offset, if @data is NULL use skb_network_offset(skb)
  507. * @hlen: packet header length, if @data is NULL use skb_headlen(skb)
  508. *
  509. * The function will try to retrieve individual keys into target specified
  510. * by flow_dissector from either the skbuff or a raw buffer specified by the
  511. * rest parameters.
  512. *
  513. * Caller must take care of zeroing target container memory.
  514. */
  515. bool __skb_flow_dissect(const struct sk_buff *skb,
  516. struct flow_dissector *flow_dissector,
  517. void *target_container,
  518. void *data, __be16 proto, int nhoff, int hlen,
  519. unsigned int flags)
  520. {
  521. struct flow_dissector_key_control *key_control;
  522. struct flow_dissector_key_basic *key_basic;
  523. struct flow_dissector_key_addrs *key_addrs;
  524. struct flow_dissector_key_ports *key_ports;
  525. struct flow_dissector_key_icmp *key_icmp;
  526. struct flow_dissector_key_tags *key_tags;
  527. struct flow_dissector_key_vlan *key_vlan;
  528. enum flow_dissect_ret fdret;
  529. enum flow_dissector_key_id dissector_vlan = FLOW_DISSECTOR_KEY_MAX;
  530. int num_hdrs = 0;
  531. u8 ip_proto = 0;
  532. bool ret;
  533. if (!data) {
  534. data = skb->data;
  535. proto = skb_vlan_tag_present(skb) ?
  536. skb->vlan_proto : skb->protocol;
  537. nhoff = skb_network_offset(skb);
  538. hlen = skb_headlen(skb);
  539. #if IS_ENABLED(CONFIG_NET_DSA)
  540. if (unlikely(skb->dev && netdev_uses_dsa(skb->dev) &&
  541. proto == htons(ETH_P_XDSA))) {
  542. const struct dsa_device_ops *ops;
  543. int offset = 0;
  544. ops = skb->dev->dsa_ptr->tag_ops;
  545. if (ops->flow_dissect &&
  546. !ops->flow_dissect(skb, &proto, &offset)) {
  547. hlen -= offset;
  548. nhoff += offset;
  549. }
  550. }
  551. #endif
  552. }
  553. /* It is ensured by skb_flow_dissector_init() that control key will
  554. * be always present.
  555. */
  556. key_control = skb_flow_dissector_target(flow_dissector,
  557. FLOW_DISSECTOR_KEY_CONTROL,
  558. target_container);
  559. /* It is ensured by skb_flow_dissector_init() that basic key will
  560. * be always present.
  561. */
  562. key_basic = skb_flow_dissector_target(flow_dissector,
  563. FLOW_DISSECTOR_KEY_BASIC,
  564. target_container);
  565. if (dissector_uses_key(flow_dissector,
  566. FLOW_DISSECTOR_KEY_ETH_ADDRS)) {
  567. struct ethhdr *eth = eth_hdr(skb);
  568. struct flow_dissector_key_eth_addrs *key_eth_addrs;
  569. key_eth_addrs = skb_flow_dissector_target(flow_dissector,
  570. FLOW_DISSECTOR_KEY_ETH_ADDRS,
  571. target_container);
  572. memcpy(key_eth_addrs, &eth->h_dest, sizeof(*key_eth_addrs));
  573. }
  574. proto_again:
  575. fdret = FLOW_DISSECT_RET_CONTINUE;
  576. switch (proto) {
  577. case htons(ETH_P_IP): {
  578. const struct iphdr *iph;
  579. struct iphdr _iph;
  580. iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
  581. if (!iph || iph->ihl < 5) {
  582. fdret = FLOW_DISSECT_RET_OUT_BAD;
  583. break;
  584. }
  585. nhoff += iph->ihl * 4;
  586. ip_proto = iph->protocol;
  587. if (dissector_uses_key(flow_dissector,
  588. FLOW_DISSECTOR_KEY_IPV4_ADDRS)) {
  589. key_addrs = skb_flow_dissector_target(flow_dissector,
  590. FLOW_DISSECTOR_KEY_IPV4_ADDRS,
  591. target_container);
  592. memcpy(&key_addrs->v4addrs, &iph->saddr,
  593. sizeof(key_addrs->v4addrs));
  594. key_control->addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
  595. }
  596. if (ip_is_fragment(iph)) {
  597. key_control->flags |= FLOW_DIS_IS_FRAGMENT;
  598. if (iph->frag_off & htons(IP_OFFSET)) {
  599. fdret = FLOW_DISSECT_RET_OUT_GOOD;
  600. break;
  601. } else {
  602. key_control->flags |= FLOW_DIS_FIRST_FRAG;
  603. if (!(flags &
  604. FLOW_DISSECTOR_F_PARSE_1ST_FRAG)) {
  605. fdret = FLOW_DISSECT_RET_OUT_GOOD;
  606. break;
  607. }
  608. }
  609. }
  610. __skb_flow_dissect_ipv4(skb, flow_dissector,
  611. target_container, data, iph);
  612. if (flags & FLOW_DISSECTOR_F_STOP_AT_L3) {
  613. fdret = FLOW_DISSECT_RET_OUT_GOOD;
  614. break;
  615. }
  616. break;
  617. }
  618. case htons(ETH_P_IPV6): {
  619. const struct ipv6hdr *iph;
  620. struct ipv6hdr _iph;
  621. iph = __skb_header_pointer(skb, nhoff, sizeof(_iph), data, hlen, &_iph);
  622. if (!iph) {
  623. fdret = FLOW_DISSECT_RET_OUT_BAD;
  624. break;
  625. }
  626. ip_proto = iph->nexthdr;
  627. nhoff += sizeof(struct ipv6hdr);
  628. if (dissector_uses_key(flow_dissector,
  629. FLOW_DISSECTOR_KEY_IPV6_ADDRS)) {
  630. key_addrs = skb_flow_dissector_target(flow_dissector,
  631. FLOW_DISSECTOR_KEY_IPV6_ADDRS,
  632. target_container);
  633. memcpy(&key_addrs->v6addrs, &iph->saddr,
  634. sizeof(key_addrs->v6addrs));
  635. key_control->addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
  636. }
  637. if ((dissector_uses_key(flow_dissector,
  638. FLOW_DISSECTOR_KEY_FLOW_LABEL) ||
  639. (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL)) &&
  640. ip6_flowlabel(iph)) {
  641. __be32 flow_label = ip6_flowlabel(iph);
  642. if (dissector_uses_key(flow_dissector,
  643. FLOW_DISSECTOR_KEY_FLOW_LABEL)) {
  644. key_tags = skb_flow_dissector_target(flow_dissector,
  645. FLOW_DISSECTOR_KEY_FLOW_LABEL,
  646. target_container);
  647. key_tags->flow_label = ntohl(flow_label);
  648. }
  649. if (flags & FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL) {
  650. fdret = FLOW_DISSECT_RET_OUT_GOOD;
  651. break;
  652. }
  653. }
  654. __skb_flow_dissect_ipv6(skb, flow_dissector,
  655. target_container, data, iph);
  656. if (flags & FLOW_DISSECTOR_F_STOP_AT_L3)
  657. fdret = FLOW_DISSECT_RET_OUT_GOOD;
  658. break;
  659. }
  660. case htons(ETH_P_8021AD):
  661. case htons(ETH_P_8021Q): {
  662. const struct vlan_hdr *vlan = NULL;
  663. struct vlan_hdr _vlan;
  664. __be16 saved_vlan_tpid = proto;
  665. if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX &&
  666. skb && skb_vlan_tag_present(skb)) {
  667. proto = skb->protocol;
  668. } else {
  669. vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan),
  670. data, hlen, &_vlan);
  671. if (!vlan) {
  672. fdret = FLOW_DISSECT_RET_OUT_BAD;
  673. break;
  674. }
  675. proto = vlan->h_vlan_encapsulated_proto;
  676. nhoff += sizeof(*vlan);
  677. }
  678. if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX) {
  679. dissector_vlan = FLOW_DISSECTOR_KEY_VLAN;
  680. } else if (dissector_vlan == FLOW_DISSECTOR_KEY_VLAN) {
  681. dissector_vlan = FLOW_DISSECTOR_KEY_CVLAN;
  682. } else {
  683. fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
  684. break;
  685. }
  686. if (dissector_uses_key(flow_dissector, dissector_vlan)) {
  687. key_vlan = skb_flow_dissector_target(flow_dissector,
  688. dissector_vlan,
  689. target_container);
  690. if (!vlan) {
  691. key_vlan->vlan_id = skb_vlan_tag_get_id(skb);
  692. key_vlan->vlan_priority =
  693. (skb_vlan_tag_get_prio(skb) >> VLAN_PRIO_SHIFT);
  694. } else {
  695. key_vlan->vlan_id = ntohs(vlan->h_vlan_TCI) &
  696. VLAN_VID_MASK;
  697. key_vlan->vlan_priority =
  698. (ntohs(vlan->h_vlan_TCI) &
  699. VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
  700. }
  701. key_vlan->vlan_tpid = saved_vlan_tpid;
  702. }
  703. fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
  704. break;
  705. }
  706. case htons(ETH_P_PPP_SES): {
  707. struct {
  708. struct pppoe_hdr hdr;
  709. __be16 proto;
  710. } *hdr, _hdr;
  711. hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data, hlen, &_hdr);
  712. if (!hdr) {
  713. fdret = FLOW_DISSECT_RET_OUT_BAD;
  714. break;
  715. }
  716. proto = hdr->proto;
  717. nhoff += PPPOE_SES_HLEN;
  718. switch (proto) {
  719. case htons(PPP_IP):
  720. proto = htons(ETH_P_IP);
  721. fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
  722. break;
  723. case htons(PPP_IPV6):
  724. proto = htons(ETH_P_IPV6);
  725. fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
  726. break;
  727. default:
  728. fdret = FLOW_DISSECT_RET_OUT_BAD;
  729. break;
  730. }
  731. break;
  732. }
  733. case htons(ETH_P_TIPC): {
  734. struct tipc_basic_hdr *hdr, _hdr;
  735. hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr),
  736. data, hlen, &_hdr);
  737. if (!hdr) {
  738. fdret = FLOW_DISSECT_RET_OUT_BAD;
  739. break;
  740. }
  741. if (dissector_uses_key(flow_dissector,
  742. FLOW_DISSECTOR_KEY_TIPC)) {
  743. key_addrs = skb_flow_dissector_target(flow_dissector,
  744. FLOW_DISSECTOR_KEY_TIPC,
  745. target_container);
  746. key_addrs->tipckey.key = tipc_hdr_rps_key(hdr);
  747. key_control->addr_type = FLOW_DISSECTOR_KEY_TIPC;
  748. }
  749. fdret = FLOW_DISSECT_RET_OUT_GOOD;
  750. break;
  751. }
  752. case htons(ETH_P_MPLS_UC):
  753. case htons(ETH_P_MPLS_MC):
  754. fdret = __skb_flow_dissect_mpls(skb, flow_dissector,
  755. target_container, data,
  756. nhoff, hlen);
  757. break;
  758. case htons(ETH_P_FCOE):
  759. if ((hlen - nhoff) < FCOE_HEADER_LEN) {
  760. fdret = FLOW_DISSECT_RET_OUT_BAD;
  761. break;
  762. }
  763. nhoff += FCOE_HEADER_LEN;
  764. fdret = FLOW_DISSECT_RET_OUT_GOOD;
  765. break;
  766. case htons(ETH_P_ARP):
  767. case htons(ETH_P_RARP):
  768. fdret = __skb_flow_dissect_arp(skb, flow_dissector,
  769. target_container, data,
  770. nhoff, hlen);
  771. break;
  772. case htons(ETH_P_BATMAN):
  773. fdret = __skb_flow_dissect_batadv(skb, key_control, data,
  774. &proto, &nhoff, hlen, flags);
  775. break;
  776. default:
  777. fdret = FLOW_DISSECT_RET_OUT_BAD;
  778. break;
  779. }
  780. /* Process result of proto processing */
  781. switch (fdret) {
  782. case FLOW_DISSECT_RET_OUT_GOOD:
  783. goto out_good;
  784. case FLOW_DISSECT_RET_PROTO_AGAIN:
  785. if (skb_flow_dissect_allowed(&num_hdrs))
  786. goto proto_again;
  787. goto out_good;
  788. case FLOW_DISSECT_RET_CONTINUE:
  789. case FLOW_DISSECT_RET_IPPROTO_AGAIN:
  790. break;
  791. case FLOW_DISSECT_RET_OUT_BAD:
  792. default:
  793. goto out_bad;
  794. }
  795. ip_proto_again:
  796. fdret = FLOW_DISSECT_RET_CONTINUE;
  797. switch (ip_proto) {
  798. case IPPROTO_GRE:
  799. fdret = __skb_flow_dissect_gre(skb, key_control, flow_dissector,
  800. target_container, data,
  801. &proto, &nhoff, &hlen, flags);
  802. break;
  803. case NEXTHDR_HOP:
  804. case NEXTHDR_ROUTING:
  805. case NEXTHDR_DEST: {
  806. u8 _opthdr[2], *opthdr;
  807. if (proto != htons(ETH_P_IPV6))
  808. break;
  809. opthdr = __skb_header_pointer(skb, nhoff, sizeof(_opthdr),
  810. data, hlen, &_opthdr);
  811. if (!opthdr) {
  812. fdret = FLOW_DISSECT_RET_OUT_BAD;
  813. break;
  814. }
  815. ip_proto = opthdr[0];
  816. nhoff += (opthdr[1] + 1) << 3;
  817. fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN;
  818. break;
  819. }
  820. case NEXTHDR_FRAGMENT: {
  821. struct frag_hdr _fh, *fh;
  822. if (proto != htons(ETH_P_IPV6))
  823. break;
  824. fh = __skb_header_pointer(skb, nhoff, sizeof(_fh),
  825. data, hlen, &_fh);
  826. if (!fh) {
  827. fdret = FLOW_DISSECT_RET_OUT_BAD;
  828. break;
  829. }
  830. key_control->flags |= FLOW_DIS_IS_FRAGMENT;
  831. nhoff += sizeof(_fh);
  832. ip_proto = fh->nexthdr;
  833. if (!(fh->frag_off & htons(IP6_OFFSET))) {
  834. key_control->flags |= FLOW_DIS_FIRST_FRAG;
  835. if (flags & FLOW_DISSECTOR_F_PARSE_1ST_FRAG) {
  836. fdret = FLOW_DISSECT_RET_IPPROTO_AGAIN;
  837. break;
  838. }
  839. }
  840. fdret = FLOW_DISSECT_RET_OUT_GOOD;
  841. break;
  842. }
  843. case IPPROTO_IPIP:
  844. proto = htons(ETH_P_IP);
  845. key_control->flags |= FLOW_DIS_ENCAPSULATION;
  846. if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) {
  847. fdret = FLOW_DISSECT_RET_OUT_GOOD;
  848. break;
  849. }
  850. fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
  851. break;
  852. case IPPROTO_IPV6:
  853. proto = htons(ETH_P_IPV6);
  854. key_control->flags |= FLOW_DIS_ENCAPSULATION;
  855. if (flags & FLOW_DISSECTOR_F_STOP_AT_ENCAP) {
  856. fdret = FLOW_DISSECT_RET_OUT_GOOD;
  857. break;
  858. }
  859. fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
  860. break;
  861. case IPPROTO_MPLS:
  862. proto = htons(ETH_P_MPLS_UC);
  863. fdret = FLOW_DISSECT_RET_PROTO_AGAIN;
  864. break;
  865. case IPPROTO_TCP:
  866. __skb_flow_dissect_tcp(skb, flow_dissector, target_container,
  867. data, nhoff, hlen);
  868. break;
  869. default:
  870. break;
  871. }
  872. if (dissector_uses_key(flow_dissector, FLOW_DISSECTOR_KEY_PORTS) &&
  873. !(key_control->flags & FLOW_DIS_IS_FRAGMENT)) {
  874. key_ports = skb_flow_dissector_target(flow_dissector,
  875. FLOW_DISSECTOR_KEY_PORTS,
  876. target_container);
  877. key_ports->ports = __skb_flow_get_ports(skb, nhoff, ip_proto,
  878. data, hlen);
  879. }
  880. if (dissector_uses_key(flow_dissector,
  881. FLOW_DISSECTOR_KEY_ICMP)) {
  882. key_icmp = skb_flow_dissector_target(flow_dissector,
  883. FLOW_DISSECTOR_KEY_ICMP,
  884. target_container);
  885. key_icmp->icmp = skb_flow_get_be16(skb, nhoff, data, hlen);
  886. }
  887. /* Process result of IP proto processing */
  888. switch (fdret) {
  889. case FLOW_DISSECT_RET_PROTO_AGAIN:
  890. if (skb_flow_dissect_allowed(&num_hdrs))
  891. goto proto_again;
  892. break;
  893. case FLOW_DISSECT_RET_IPPROTO_AGAIN:
  894. if (skb_flow_dissect_allowed(&num_hdrs))
  895. goto ip_proto_again;
  896. break;
  897. case FLOW_DISSECT_RET_OUT_GOOD:
  898. case FLOW_DISSECT_RET_CONTINUE:
  899. break;
  900. case FLOW_DISSECT_RET_OUT_BAD:
  901. default:
  902. goto out_bad;
  903. }
  904. out_good:
  905. ret = true;
  906. out:
  907. key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen);
  908. key_basic->n_proto = proto;
  909. key_basic->ip_proto = ip_proto;
  910. return ret;
  911. out_bad:
  912. ret = false;
  913. goto out;
  914. }
  915. EXPORT_SYMBOL(__skb_flow_dissect);
  916. static siphash_key_t hashrnd __read_mostly;
  917. static __always_inline void __flow_hash_secret_init(void)
  918. {
  919. net_get_random_once(&hashrnd, sizeof(hashrnd));
  920. }
  921. static const void *flow_keys_hash_start(const struct flow_keys *flow)
  922. {
  923. BUILD_BUG_ON(FLOW_KEYS_HASH_OFFSET % SIPHASH_ALIGNMENT);
  924. return &flow->FLOW_KEYS_HASH_START_FIELD;
  925. }
  926. static inline size_t flow_keys_hash_length(const struct flow_keys *flow)
  927. {
  928. size_t diff = FLOW_KEYS_HASH_OFFSET + sizeof(flow->addrs);
  929. BUILD_BUG_ON(offsetof(typeof(*flow), addrs) !=
  930. sizeof(*flow) - sizeof(flow->addrs));
  931. switch (flow->control.addr_type) {
  932. case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
  933. diff -= sizeof(flow->addrs.v4addrs);
  934. break;
  935. case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
  936. diff -= sizeof(flow->addrs.v6addrs);
  937. break;
  938. case FLOW_DISSECTOR_KEY_TIPC:
  939. diff -= sizeof(flow->addrs.tipckey);
  940. break;
  941. }
  942. return sizeof(*flow) - diff;
  943. }
  944. __be32 flow_get_u32_src(const struct flow_keys *flow)
  945. {
  946. switch (flow->control.addr_type) {
  947. case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
  948. return flow->addrs.v4addrs.src;
  949. case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
  950. return (__force __be32)ipv6_addr_hash(
  951. &flow->addrs.v6addrs.src);
  952. case FLOW_DISSECTOR_KEY_TIPC:
  953. return flow->addrs.tipckey.key;
  954. default:
  955. return 0;
  956. }
  957. }
  958. EXPORT_SYMBOL(flow_get_u32_src);
  959. __be32 flow_get_u32_dst(const struct flow_keys *flow)
  960. {
  961. switch (flow->control.addr_type) {
  962. case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
  963. return flow->addrs.v4addrs.dst;
  964. case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
  965. return (__force __be32)ipv6_addr_hash(
  966. &flow->addrs.v6addrs.dst);
  967. default:
  968. return 0;
  969. }
  970. }
  971. EXPORT_SYMBOL(flow_get_u32_dst);
  972. static inline void __flow_hash_consistentify(struct flow_keys *keys)
  973. {
  974. int addr_diff, i;
  975. switch (keys->control.addr_type) {
  976. case FLOW_DISSECTOR_KEY_IPV4_ADDRS:
  977. addr_diff = (__force u32)keys->addrs.v4addrs.dst -
  978. (__force u32)keys->addrs.v4addrs.src;
  979. if ((addr_diff < 0) ||
  980. (addr_diff == 0 &&
  981. ((__force u16)keys->ports.dst <
  982. (__force u16)keys->ports.src))) {
  983. swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst);
  984. swap(keys->ports.src, keys->ports.dst);
  985. }
  986. break;
  987. case FLOW_DISSECTOR_KEY_IPV6_ADDRS:
  988. addr_diff = memcmp(&keys->addrs.v6addrs.dst,
  989. &keys->addrs.v6addrs.src,
  990. sizeof(keys->addrs.v6addrs.dst));
  991. if ((addr_diff < 0) ||
  992. (addr_diff == 0 &&
  993. ((__force u16)keys->ports.dst <
  994. (__force u16)keys->ports.src))) {
  995. for (i = 0; i < 4; i++)
  996. swap(keys->addrs.v6addrs.src.s6_addr32[i],
  997. keys->addrs.v6addrs.dst.s6_addr32[i]);
  998. swap(keys->ports.src, keys->ports.dst);
  999. }
  1000. break;
  1001. }
  1002. }
  1003. static inline u32 __flow_hash_from_keys(struct flow_keys *keys,
  1004. const siphash_key_t *keyval)
  1005. {
  1006. u32 hash;
  1007. __flow_hash_consistentify(keys);
  1008. hash = siphash(flow_keys_hash_start(keys),
  1009. flow_keys_hash_length(keys), keyval);
  1010. if (!hash)
  1011. hash = 1;
  1012. return hash;
  1013. }
  1014. u32 flow_hash_from_keys(struct flow_keys *keys)
  1015. {
  1016. __flow_hash_secret_init();
  1017. return __flow_hash_from_keys(keys, &hashrnd);
  1018. }
  1019. EXPORT_SYMBOL(flow_hash_from_keys);
  1020. static inline u32 ___skb_get_hash(const struct sk_buff *skb,
  1021. struct flow_keys *keys,
  1022. const siphash_key_t *keyval)
  1023. {
  1024. skb_flow_dissect_flow_keys(skb, keys,
  1025. FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
  1026. return __flow_hash_from_keys(keys, keyval);
  1027. }
  1028. struct _flow_keys_digest_data {
  1029. __be16 n_proto;
  1030. u8 ip_proto;
  1031. u8 padding;
  1032. __be32 ports;
  1033. __be32 src;
  1034. __be32 dst;
  1035. };
  1036. void make_flow_keys_digest(struct flow_keys_digest *digest,
  1037. const struct flow_keys *flow)
  1038. {
  1039. struct _flow_keys_digest_data *data =
  1040. (struct _flow_keys_digest_data *)digest;
  1041. BUILD_BUG_ON(sizeof(*data) > sizeof(*digest));
  1042. memset(digest, 0, sizeof(*digest));
  1043. data->n_proto = flow->basic.n_proto;
  1044. data->ip_proto = flow->basic.ip_proto;
  1045. data->ports = flow->ports.ports;
  1046. data->src = flow->addrs.v4addrs.src;
  1047. data->dst = flow->addrs.v4addrs.dst;
  1048. }
  1049. EXPORT_SYMBOL(make_flow_keys_digest);
  1050. static struct flow_dissector flow_keys_dissector_symmetric __read_mostly;
  1051. u32 __skb_get_hash_symmetric(const struct sk_buff *skb)
  1052. {
  1053. struct flow_keys keys;
  1054. __flow_hash_secret_init();
  1055. memset(&keys, 0, sizeof(keys));
  1056. __skb_flow_dissect(skb, &flow_keys_dissector_symmetric, &keys,
  1057. NULL, 0, 0, 0,
  1058. FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL);
  1059. return __flow_hash_from_keys(&keys, &hashrnd);
  1060. }
  1061. EXPORT_SYMBOL_GPL(__skb_get_hash_symmetric);
  1062. /**
  1063. * __skb_get_hash: calculate a flow hash
  1064. * @skb: sk_buff to calculate flow hash from
  1065. *
  1066. * This function calculates a flow hash based on src/dst addresses
  1067. * and src/dst port numbers. Sets hash in skb to non-zero hash value
  1068. * on success, zero indicates no valid hash. Also, sets l4_hash in skb
  1069. * if hash is a canonical 4-tuple hash over transport ports.
  1070. */
  1071. void __skb_get_hash(struct sk_buff *skb)
  1072. {
  1073. struct flow_keys keys;
  1074. u32 hash;
  1075. __flow_hash_secret_init();
  1076. hash = ___skb_get_hash(skb, &keys, &hashrnd);
  1077. __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys));
  1078. }
  1079. EXPORT_SYMBOL(__skb_get_hash);
  1080. __u32 skb_get_hash_perturb(const struct sk_buff *skb,
  1081. const siphash_key_t *perturb)
  1082. {
  1083. struct flow_keys keys;
  1084. return ___skb_get_hash(skb, &keys, perturb);
  1085. }
  1086. EXPORT_SYMBOL(skb_get_hash_perturb);
  1087. u32 __skb_get_poff(const struct sk_buff *skb, void *data,
  1088. const struct flow_keys_basic *keys, int hlen)
  1089. {
  1090. u32 poff = keys->control.thoff;
  1091. /* skip L4 headers for fragments after the first */
  1092. if ((keys->control.flags & FLOW_DIS_IS_FRAGMENT) &&
  1093. !(keys->control.flags & FLOW_DIS_FIRST_FRAG))
  1094. return poff;
  1095. switch (keys->basic.ip_proto) {
  1096. case IPPROTO_TCP: {
  1097. /* access doff as u8 to avoid unaligned access */
  1098. const u8 *doff;
  1099. u8 _doff;
  1100. doff = __skb_header_pointer(skb, poff + 12, sizeof(_doff),
  1101. data, hlen, &_doff);
  1102. if (!doff)
  1103. return poff;
  1104. poff += max_t(u32, sizeof(struct tcphdr), (*doff & 0xF0) >> 2);
  1105. break;
  1106. }
  1107. case IPPROTO_UDP:
  1108. case IPPROTO_UDPLITE:
  1109. poff += sizeof(struct udphdr);
  1110. break;
  1111. /* For the rest, we do not really care about header
  1112. * extensions at this point for now.
  1113. */
  1114. case IPPROTO_ICMP:
  1115. poff += sizeof(struct icmphdr);
  1116. break;
  1117. case IPPROTO_ICMPV6:
  1118. poff += sizeof(struct icmp6hdr);
  1119. break;
  1120. case IPPROTO_IGMP:
  1121. poff += sizeof(struct igmphdr);
  1122. break;
  1123. case IPPROTO_DCCP:
  1124. poff += sizeof(struct dccp_hdr);
  1125. break;
  1126. case IPPROTO_SCTP:
  1127. poff += sizeof(struct sctphdr);
  1128. break;
  1129. }
  1130. return poff;
  1131. }
  1132. /**
  1133. * skb_get_poff - get the offset to the payload
  1134. * @skb: sk_buff to get the payload offset from
  1135. *
  1136. * The function will get the offset to the payload as far as it could
  1137. * be dissected. The main user is currently BPF, so that we can dynamically
  1138. * truncate packets without needing to push actual payload to the user
  1139. * space and can analyze headers only, instead.
  1140. */
  1141. u32 skb_get_poff(const struct sk_buff *skb)
  1142. {
  1143. struct flow_keys_basic keys;
  1144. if (!skb_flow_dissect_flow_keys_basic(skb, &keys, NULL, 0, 0, 0, 0))
  1145. return 0;
  1146. return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
  1147. }
  1148. __u32 __get_hash_from_flowi6(const struct flowi6 *fl6, struct flow_keys *keys)
  1149. {
  1150. memset(keys, 0, sizeof(*keys));
  1151. memcpy(&keys->addrs.v6addrs.src, &fl6->saddr,
  1152. sizeof(keys->addrs.v6addrs.src));
  1153. memcpy(&keys->addrs.v6addrs.dst, &fl6->daddr,
  1154. sizeof(keys->addrs.v6addrs.dst));
  1155. keys->control.addr_type = FLOW_DISSECTOR_KEY_IPV6_ADDRS;
  1156. keys->ports.src = fl6->fl6_sport;
  1157. keys->ports.dst = fl6->fl6_dport;
  1158. keys->keyid.keyid = fl6->fl6_gre_key;
  1159. keys->tags.flow_label = (__force u32)flowi6_get_flowlabel(fl6);
  1160. keys->basic.ip_proto = fl6->flowi6_proto;
  1161. return flow_hash_from_keys(keys);
  1162. }
  1163. EXPORT_SYMBOL(__get_hash_from_flowi6);
  1164. static const struct flow_dissector_key flow_keys_dissector_keys[] = {
  1165. {
  1166. .key_id = FLOW_DISSECTOR_KEY_CONTROL,
  1167. .offset = offsetof(struct flow_keys, control),
  1168. },
  1169. {
  1170. .key_id = FLOW_DISSECTOR_KEY_BASIC,
  1171. .offset = offsetof(struct flow_keys, basic),
  1172. },
  1173. {
  1174. .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
  1175. .offset = offsetof(struct flow_keys, addrs.v4addrs),
  1176. },
  1177. {
  1178. .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
  1179. .offset = offsetof(struct flow_keys, addrs.v6addrs),
  1180. },
  1181. {
  1182. .key_id = FLOW_DISSECTOR_KEY_TIPC,
  1183. .offset = offsetof(struct flow_keys, addrs.tipckey),
  1184. },
  1185. {
  1186. .key_id = FLOW_DISSECTOR_KEY_PORTS,
  1187. .offset = offsetof(struct flow_keys, ports),
  1188. },
  1189. {
  1190. .key_id = FLOW_DISSECTOR_KEY_VLAN,
  1191. .offset = offsetof(struct flow_keys, vlan),
  1192. },
  1193. {
  1194. .key_id = FLOW_DISSECTOR_KEY_FLOW_LABEL,
  1195. .offset = offsetof(struct flow_keys, tags),
  1196. },
  1197. {
  1198. .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID,
  1199. .offset = offsetof(struct flow_keys, keyid),
  1200. },
  1201. };
  1202. static const struct flow_dissector_key flow_keys_dissector_symmetric_keys[] = {
  1203. {
  1204. .key_id = FLOW_DISSECTOR_KEY_CONTROL,
  1205. .offset = offsetof(struct flow_keys, control),
  1206. },
  1207. {
  1208. .key_id = FLOW_DISSECTOR_KEY_BASIC,
  1209. .offset = offsetof(struct flow_keys, basic),
  1210. },
  1211. {
  1212. .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS,
  1213. .offset = offsetof(struct flow_keys, addrs.v4addrs),
  1214. },
  1215. {
  1216. .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS,
  1217. .offset = offsetof(struct flow_keys, addrs.v6addrs),
  1218. },
  1219. {
  1220. .key_id = FLOW_DISSECTOR_KEY_PORTS,
  1221. .offset = offsetof(struct flow_keys, ports),
  1222. },
  1223. };
  1224. static const struct flow_dissector_key flow_keys_basic_dissector_keys[] = {
  1225. {
  1226. .key_id = FLOW_DISSECTOR_KEY_CONTROL,
  1227. .offset = offsetof(struct flow_keys, control),
  1228. },
  1229. {
  1230. .key_id = FLOW_DISSECTOR_KEY_BASIC,
  1231. .offset = offsetof(struct flow_keys, basic),
  1232. },
  1233. };
  1234. struct flow_dissector flow_keys_dissector __read_mostly;
  1235. EXPORT_SYMBOL(flow_keys_dissector);
  1236. struct flow_dissector flow_keys_basic_dissector __read_mostly;
  1237. EXPORT_SYMBOL(flow_keys_basic_dissector);
  1238. static int __init init_default_flow_dissectors(void)
  1239. {
  1240. skb_flow_dissector_init(&flow_keys_dissector,
  1241. flow_keys_dissector_keys,
  1242. ARRAY_SIZE(flow_keys_dissector_keys));
  1243. skb_flow_dissector_init(&flow_keys_dissector_symmetric,
  1244. flow_keys_dissector_symmetric_keys,
  1245. ARRAY_SIZE(flow_keys_dissector_symmetric_keys));
  1246. skb_flow_dissector_init(&flow_keys_basic_dissector,
  1247. flow_keys_basic_dissector_keys,
  1248. ARRAY_SIZE(flow_keys_basic_dissector_keys));
  1249. return 0;
  1250. }
  1251. core_initcall(init_default_flow_dissectors);